小编给大家分享一下c#如何批量抓取免费代理并且验证有效性，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！
1.从哪些网页上可以抓取免费的代理IP？
百度一下“免费代理ip”挺多的。
2.代理IP稳定吗？有什么作用？
这种免费的代理ip时效性和有效性都不强，上面这三个免费的代理网站，时效性大概在十几秒到1个小时不等，一般需要自己处理验证后使用，提高命中率。可适用于隐藏网页IP（有些网站还不准使用代理ip，比如豆瓣，其实挺尴尬的，内容这么贵吗），一般常用于空间留言、刷网站流量、网赚任务、批量注册账号等，只要没有其他限制，需要频繁更换ip都可以使用。
3.ping通IP就是有效的吗？如何验证代理是否有效
好吧，这有点废话，进行端口测试才是最有效的，能ping通并不代表代理有效，不能平通也不一定代理不可用。可以使用HttpWebRequest，也可以使用Scoket，当然HttpWebRequest比Socket连接代理ip、port要慢。
4.一次提取多少代理合适？
代理ip时效性不强、并且有效性也不高，所以只能从一些代理ip的网站上批量定时去获取，有的代理在一分钟内使用是有限制的，所以说限制比较多。
5.http代理和https代理有什么区别？
需要访问https的网站就需要使用https代理了，比如百度，需要访问http的代理，可以使用http。这个并不是100%的。
检测代理ip有效性步骤如下：
1.使用HttpWebRequest、HttpWebResponse请求代理ip的网页，获取包含代理的网页内容
2.使用HtmlAgilityPack或者正则表达式对抓取的内容进行截取，保存到代理集合
3.拿到代理集合，多线程发起http请求，比如访问百度，是否成功，成功则存到Redis里面。
效果图如下：
使用HttpWebRequest发起请求
Request.cs如下，主要就是两个方法，一个方法是验证代理ip是否有效，设置HttpWebRequest的Proxy属性，请求百度，看到有些文章大多数会获取响应的内容，如果内容符合请求的网址则证明代理哟有效，实际上根据HttpStatusCode 200就可以判断是否验证有效。
【注意】建的是控制台程序，使用了异步，所以还是建.net core吧，c#语言的版本7.1。C#如何在控制台程序中使用异步
public class Request { /// <summary> /// 验证代理ip有效性 /// </summary> /// <param name="proxyIp">代理IP</param> /// <param name="proxyPort">代理IP 端口</param> /// <param name="timeout">详情超时</param> /// <param name="url">请求的地址</param> /// <param name="success">成功的回调</param> /// <param name="fail">失败的回调</param> /// <returns></returns> public static async System.Threading.Tasks.Task getAsync(string proxyIp,int proxyPort, int timeout,string url, Action success, Action<string> fail) { System.GC.Collect(); HttpWebRequest request = null; HttpWebResponse response = null; try { request = (HttpWebRequest)WebRequest.Create(url); //HttpWebRequest request = HttpWebRequest.CreateHttp(url); request.Timeout =timeout; request.KeepAlive = false; request.Proxy = new WebProxy(proxyIp,proxyPort); response = await request.GetResponseAsync() as HttpWebResponse; if (response.StatusCode == HttpStatusCode.OK) { success(); } else { fail(response.StatusCode+":"+response.StatusDescription); } } catch (Exception ex) { fail("请求异常"+ex.Message.ToString()); } finally { if (request != null) { request.Abort(); request = null; } if (response != null) { response.Close(); } } } /// <summary> /// 发起http请求 /// </summary> /// <param name="url"></param> /// <param name="success">成功的回调</param> /// <param name="fail">失败的回调</param> public static void get(string url,Action<string> success,Action<string> fail) { StreamReader reader = null; Stream stream = null; WebRequest request = null; HttpWebResponse response = null; try { request = WebRequest.Create(url); request.Timeout = 2000; response = (HttpWebResponse)request.GetResponse(); if (response.StatusCode == HttpStatusCode.OK) { stream = response.GetResponseStream(); reader = new StreamReader(stream); string result = reader.ReadToEnd(); success(result); } else { fail(response.StatusCode+":"+response.StatusDescription); } } catch (Exception ex) { fail(ex.ToString()); } finally { if (reader != null) reader.Close(); if (stream != null) stream.Close(); if(response!=null) response.Close(); if(request!=null) request.Abort(); } } }抓取免费代理，并检查是否有效
ProxyIpHelper.cs 中主要有四个方法，检查ip是否可用CheckProxyIpAsync、抓取xicidaili.com的代理GetXicidailiProxy、抓取ip3366.net的代理GetIp3366Proxy、抓取66ip.cn的代理GetIp3366Proxy。如果想多抓取几个网站可以多写几个。
public class ProxyIpHelper { private static string address_xicidaili = "http://www.xicidaili.com/wn/{0}"; private static string address_66ip = "http://www.66ip.cn/nmtq.php?getnum=20&isp=0&anonymoustype=0&start=&ports=&export=&ipaddress=&area=1&proxytype=1&api=66ip"; private static string address_ip3366 = "http://www.ip3366.net/?stype=1&page={0}"; /// <summary> /// 检查代理IP是否可用 /// </summary> /// <param name="ipAddress">ip</param> /// <param name="success">成功的回调</param> /// <param name="fail">失败的回调</param> /// <returns></returns> public static async Task CheckProxyIpAsync(string ipAddress, Action success, Action<string> fail) { int index = ipAddress.IndexOf(":"); string proxyIp = ipAddress.Substring(0, index); int proxyPort = int.Parse(ipAddress.Substring(index + 1)); await Request.getAsync(proxyIp, proxyPort, 3000, "https://www.baidu.com/", () => { success(); }, (error) => { fail(error); }); } /// <summary> /// 从xicidaili.com网页上去获取代理IP，可以分页 /// </summary> /// <param name="page"></param> /// <returns></returns> public static List<string> GetXicidailiProxy(int page) { List<string> list = new List<string>(); for (int p = 1; p <= page; p++) { string url = string.Format(address_xicidaili, p); Request.get(url,(docText)=> { if (!string.IsNullOrWhiteSpace(docText)) { HtmlDocument doc = new HtmlDocument(); doc.LoadHtml(docText); var trNodes = doc.DocumentNode.SelectNodes("//table[@id='ip_list']")[0].SelectNodes("./tr"); if (trNodes != null && trNodes.Count > 0) { for (int i = 1; i < trNodes.Count; i++) { var tds = trNodes[i].SelectNodes("./td"); string ipAddress = tds[1].InnerText + ":" + int.Parse(tds[2].InnerText); ; list.Add(ipAddress); } } } },(error)=> { Console.WriteLine(error); }); } return list; } /// <summary> /// 从ip3366.net网页上去获取代理IP，可以分页 /// </summary> /// <param name="page"></param> /// <returns></returns> public static List<string> GetIp3366Proxy(int page) { List<string> list = new List<string>(); for (int p = 1; p <= page; p++) { string url = string.Format(address_ip3366, p); Request.get(url, (docText) => { if (!string.IsNullOrWhiteSpace(docText)) { HtmlDocument doc = new HtmlDocument(); doc.LoadHtml(docText); var trNodes1 = doc.DocumentNode.SelectNodes("//table")[0]; var trNodes2 = doc.DocumentNode.SelectNodes("//table")[0].SelectSingleNode("//tbody"); var trNodes = doc.DocumentNode.SelectNodes("//table")[0].SelectSingleNode("//tbody").SelectNodes("./tr"); if (trNodes != null && trNodes.Count > 0) { for (int i = 1; i < trNodes.Count; i++) { var tds = trNodes[i].SelectNodes("./td"); if (tds[3].InnerHtml == "HTTPS") { string ipAddress = tds[0].InnerText + ":" + int.Parse(tds[1].InnerText); ; list.Add(ipAddress); } } } } }, (error) => { Console.WriteLine(error); }); } return list; } /// <summary> /// 从66ip.cn中去获取，不需要分页 /// </summary> /// <returns></returns> public static List<string> Get66ipProxy() { List<string> list = new List<string>(); Request.get(address_66ip, (docText)=> { int count = 0; if (string.IsNullOrWhiteSpace(docText) == false) { string regex = "\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\:\\d{1,5}"; Match mstr = Regex.Match(docText, regex); while (mstr.Success && count < 20) { string tempIp = mstr.Groups[0].Value; list.Add(tempIp); mstr = mstr.NextMatch(); count++; } } }, (error)=> { Console.WriteLine(error); }); return list; } }使用Timer定时抓取，并检查，成功则保存到redis
c#有三种定时器，这里定时器是使用System.Threading命名空间， 这个Timer会开启新的线程，抓取三个网页定义了三个Timer对象。每一次抓取都会保存上一次抓取的集合，检查前，会进行对比，取出新的集合也就是没有重复的那部分。有效性的ip比较低，这里没有做统计，如果代码再优化一下，可以做一下统计，看看程序的主入口吧，最终的实现如下：
class Program { static bool timer_ip3366_isCompleted = true; static bool timer_xicidaili_isCompleted = true; static bool timer_66ip_isCompleted = true; static Timer timer_ip3366, timer_xicidaili, timer_66ip; private static List<string> lastListip3366,lastList66ip,lastListxicidaili;//保存上一次抓取的代理，与下一次进行对比，取新的集合进行检查筛选 static async Task Main(string[] args) { System.Net.ServicePointManager.DefaultConnectionLimit = 2000; Console.WriteLine("hellow proxyIp"); Console.ReadLine(); lastList66ip = new List<string>(); lastListip3366 = new List<string>(); lastListxicidaili = new List<string>(); timer_ip3366 = new Timer(async (state) => { await TimerIp3366Async(); }, "processing timer_ip3366 event", 0,1000*30); timer_xicidaili = new Timer(async (state) => { await TimerXicidailiAsync(); }, "processing timer_xicidaili event", 0, 1000 * 60); timer_66ip = new Timer(async (state) => { await Timer66ipAsync(); }, "processing timer_66ip event", 0, 1000*30); Console.ReadLine(); } private static async Task Timer66ipAsync() { if (timer_66ip_isCompleted) { timer_66ip_isCompleted = false; List<string> checkList = new List<string>(); var listProxyIp = ProxyIpHelper.Get66ipProxy(); if (listProxyIp.Count > 0) { Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("66ip.cn 抓取到" + listProxyIp.Count + "条记录,正在对比........."); listProxyIp.ForEach(f => { if (!lastList66ip.Contains(f)) { checkList.Add(f); } }); lastList66ip = listProxyIp; if (checkList.Count > 0) { Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("66ip.cn 需要检查" + checkList.Count + "条记录,正在进行检测是否有效.........."); for (int i = 0; i < checkList.Count; i++) { string ipAddress = checkList[i]; await ProxyIpHelper.CheckProxyIpAsync(ipAddress, () => { bool insertSuccess = RedisHelper.InsertSet(ipAddress); Console.ForegroundColor = ConsoleColor.White; Console.WriteLine("66ip.cn"); if (insertSuccess) { Console.WriteLine("success" + ipAddress + "任务编号:" + i + "当前任务线程:" + Thread.CurrentThread.ManagedThreadId); } Console.WriteLine("重复插入" + ipAddress + "任务编号:" + i + "当前任务线程:" + Thread.CurrentThread.ManagedThreadId); }, (error) => { Console.ForegroundColor = ConsoleColor.Green; Console.WriteLine("66ip.cn"); Console.WriteLine("error:" + ipAddress + error + "任务编号:" + i + "当前任务线程:" + Thread.CurrentThread.ManagedThreadId); }); } timer_66ip_isCompleted = true; Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("66ip.cn" + checkList.Count + "条记录,已经检测完成，正在进行下一次检查"); } else { timer_66ip_isCompleted = true; Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("66ip.cn没有需要检查的代理ip"); } } else { timer_66ip_isCompleted = true; Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("66ip.cn没有获取到代理ip"); } } } private static async Task TimerXicidailiAsync() { if (timer_xicidaili_isCompleted) { //取出需要检查的ip地址，第一次100条则checklist就是100条记录， //第二次的100条中只有10是和上一次的不重复，则第二次只需要检查这10条记录 timer_xicidaili_isCompleted = false; List<string> checkList = new List<string>(); var listProxyIp = ProxyIpHelper.GetXicidailiProxy(1); if (listProxyIp.Count > 0) { Console.WriteLine("xicidaili.com 抓取到" + listProxyIp.Count + "条记录,正在对比............"); listProxyIp.ForEach(f => { if (!lastListxicidaili.Contains(f)) { checkList.Add(f); } }); lastListxicidaili = listProxyIp; if (checkList.Count > 0) { Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("xicidaili.com 需要检查" + checkList.Count + "条记录,正在进行检测是否有效.........."); for (int i = 0; i < checkList.Count; i++) { string ipAddress = checkList[i]; await ProxyIpHelper.CheckProxyIpAsync(ipAddress, () => { bool insertSuccess = RedisHelper.InsertSet(ipAddress); Console.ForegroundColor = ConsoleColor.White; Console.WriteLine("xicidaili.com"); if (insertSuccess) { Console.WriteLine("success" + ipAddress + "任务编号:" + i + "当前任务线程:" + Thread.CurrentThread.ManagedThreadId); } else Console.WriteLine("重复插入" + ipAddress + "任务编号:" + i + "当前任务线程:" + Thread.CurrentThread.ManagedThreadId); }, (error) => { Console.WriteLine("xicidaili.com"); Console.ForegroundColor = ConsoleColor.Red; Console.WriteLine("error:" + ipAddress + error + "任务编号:" + i + "当前任务线程:" + Thread.CurrentThread.ManagedThreadId); }); } timer_xicidaili_isCompleted = true; Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("xicidaili.com" + checkList.Count + "条记录,已经检测完成，正在进行下一次检查"); } else { timer_xicidaili_isCompleted = true; Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("xicidaili.com没有需要检查的代理ip"); } } else { timer_xicidaili_isCompleted = true; Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("xicidaili.com没有获取到代理ip"); } } } private static async Task TimerIp3366Async() { if (timer_ip3366_isCompleted) { timer_ip3366_isCompleted = false; List<string> checkList = new List<string>(); var listProxyIp = ProxyIpHelper.GetIp3366Proxy(4); if (listProxyIp.Count > 0) { Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("ip3366.net 抓取到" + listProxyIp.Count + "条记录,正在进行检测是否有效.........."); listProxyIp.ForEach(f => { if (!lastListip3366.Contains(f)) { checkList.Add(f); } }); lastListip3366 = listProxyIp; if (checkList.Count != 0) { Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("ip3366.net 需要检查" + checkList.Count + "条记录,正在进行检测是否有效.........."); for (int i = 0; i < checkList.Count; i++) { string ipAddress = checkList[i]; await ProxyIpHelper.CheckProxyIpAsync(ipAddress, () => { bool insertSuccess = RedisHelper.InsertSet(ipAddress); Console.ForegroundColor = ConsoleColor.White; Console.WriteLine("ip3366.net"); if (insertSuccess) { Console.WriteLine("success" + ipAddress + "任务编号:" + i + "当前任务线程:" + Thread.CurrentThread.ManagedThreadId); } else { Console.ForegroundColor = ConsoleColor.Red; Console.WriteLine("重复插入" + ipAddress + "任务编号:" + i + "当前任务线程:" + Thread.CurrentThread.ManagedThreadId); } }, (error) => { Console.ForegroundColor = ConsoleColor.Yellow; Console.WriteLine("ip3366.net"); Console.WriteLine("error " + ipAddress + "任务编号:" + i + "当前任务线程:" + Thread.CurrentThread.ManagedThreadId); }); } timer_ip3366_isCompleted = true; Console.WriteLine("ip3366.net" + checkList.Count + "条记录,已经检测完成，正在进行下一次检查"); } else { timer_ip3366_isCompleted = true; Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("ip3366.net没有需要检查的代理ip"); } } else { timer_ip3366_isCompleted = true; Console.ForegroundColor = ConsoleColor.DarkCyan; Console.WriteLine("ip3366.net没有获取到代理ip"); } } } }Redis第三库使用的stackoverflow的 StackExchange.Redis，代理ip不能重复储存，所以采用的数据结构是Set。存的值非常简单就一个ip加上port，也可以存入更多相关信息，感觉没必要。即使有这些其他的信息，也很难发挥作用。RedisHelper.cs如下
public class RedisHelper { private static readonly object Locker = new object(); private static ConnectionMultiplexer _redis; private const string CONNECTTIONSTRING = "127.0.0.1:6379,DefaultDatabase=3"; public const string REDIS_SET_KET_SUCCESS = "set_success_ip"; private static ConnectionMultiplexer Manager { get { if (_redis == null) { lock (Locker) { if (_redis != null) return _redis; _redis = GetManager(); return _redis; } } return _redis; } } private static ConnectionMultiplexer GetManager(string connectionString = null) { if (string.IsNullOrEmpty(connectionString)) { connectionString = CONNECTTIONSTRING; } return ConnectionMultiplexer.Connect(connectionString); } public static bool InsertSet(string value) { var db = Manager.GetDatabase(); return db.SetAdd(REDIS_SET_KET_SUCCESS,value); } }以上是“c#如何批量抓取免费代理并且验证有效性”这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注亿速云行业资讯频道！
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